Exercise is crucial to the health and quality of life of older persons. This project will develop an interactive system to help older users (>60 years of age) adopt and maintain an exercise program tailored to their personal interests. It will assess each user's fitness level and activity goals, and will recommend an appropriate exercise prescription. On-screen video peer-models, tailored by gender and relative age (<75 years; >75 years), will offer encouragement and support, including tips to overcome user-identified barriers to exercise. Increased endurance, strength, balance, and flexibility will be promoted. Users may select from demonstrated exercises, or other recommended activities. Separate program components will offer: exercises for arthritis-sufferers, exercises in a seated position, guided Tai Chi-moves, and a Library of age-relevant articles. The system will provide assistance in setting up an individualized exercise plan, including an activity schedule and an appointment for a return visit, in which colorful charting functions and additional video peer-support will encourage users as they adjust their fitness goals to maintain an exercise habit. Delivered via Internet/Intranet or CD/DVD-ROM, the system may be used from homes or in conjunction with classes in senior centers. The program will be evaluated in a randomized trial.